Field
Embodiments of the present disclosure generally relate to a semiconductor processing chamber, and more specifically, to a substrate support assembly in a semiconductor processing chamber.
Description of the Related Art
Semiconductor processing involves a number of different chemical and physical processes to create minute integrated circuits on a substrate. Layers of materials which make up the integrated circuit are created by processes including chemical vapor deposition, physical vapor deposition, epitaxial growth, and the like. Some of the layers of material are patterned using photoresist masks and wet or dry etching techniques. The substrates utilized to form integrated circuits may be silicon, gallium arsenide, indium phosphide, glass, or other appropriate materials.
In the manufacture of integrated circuits, plasma processes are often used for depositing or etching of various material layers. Plasma processing offers many advantages over thermal processing. For example, plasma enhanced chemical vapor deposition (PECVD) allows deposition processes to be performed at lower temperatures and at higher deposition rates than achievable in analogous thermal processes. Thus, PECVD is advantageous for integrated circuit fabrication with stringent thermal budgets, such as for very large scale or ultra-large scale integrated circuit (VLSI or ULSI) device fabrication.
The processing chambers used in these processes typically include a substrate support assembly having a substrate support, such as an electrostatic chuck (ESC), disposed therein to secure the substrate during processing. The substrate support assembly may include a radio frequency (RF) electrode embedded in the substrate support and a rod connecting the RF electrode to a reference voltage, such as the ground, for an RF current to travel from the RF electrode to the reference voltage. Conventionally the rod is made of nickel (Ni), which generates heat, leading to hot spots on a top surface of the substrate support, which in turn leads to thickness non-uniformity in layer formed on a substrate disposed on the top surface of the substrate support.
Therefore, there is a need for an improved substrate support assembly.